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Fixed-mobile convergence: Dual-mode versus cellular-only

There are two main approaches to fixed-mobile convergence: cellular-only and dual-mode Wi-Fi/cellular. Each approach has benefits and challenges. At Interop this week, vendors on both sides of the issue will debate what enterprises should choose.

There are two main approaches to fixed-mobile convergence today: cellular-only and dual-mode. Both have their pros and cons. It's up to the individual enterprise to determine which approach is best for it.

Fixed-mobile convergence (FMC) is the method of creating seamless connectivity between wired and wireless communications. In the cellular-only approach, enterprises can program a PBX to ring users' desk phones and cell phones simultaneously and to port other common PBX desk phone features onto cell phones.

The dual-mode FMC approach relies on third-party software to automatically transfer phone calls seamlessly between a cellular and Wi-Fi network, depending on where the user is.

More and more enterprises are recognizing the business value of FMC. However, mobile carriers have zero interest in providing a solution, according to Michael Finneran, principal of the consultancy dBrn Associates. This is a challenge to enterprises, since carrier networks have to be a part of an FMC solution no matter which approach they choose.

This Wednesday at Interop in New York, Finneran will moderate a debate on the fixed-mobile convergence industry. The panel will feature representatives from Agito Networks, DiVitas Networks and Siemens Enterprise Communications, all vendors that facilitate the automated hand-off between cellular and Wi-Fi networks on dual-mode mobile phones. The panel will also feature a representative of ADC, a company that builds distributed antenna systems that enhance indoor cellular coverage for companies that rely on a cellular-only approach to FMC. Missing from the panel, Finneran said, will be any representative from an actual mobile carrier.

"The cellular carriers have simply walked away from convergence," he said. "They have no interest. We couldn't even get someone from Verizon to participate in the panel. That tells you what these guys think of FMC."

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There are various advantages to installing fixed-mobile convergence in an enterprise. Some believe it can save money on cellular charges, but Finneran said that's dubious because the technology makes employees more reachable, so naturally they talk longer on the phone.

FMC does improve accessibility and productivity of employees.

"What we're getting at is making key people accessible, so now you have one phone number and someone calls it. Whether you're on the road or in the office, they can get you," Finneran said. "It's about reaching people. You can also get some swell productivity features. Now you've got one voicemail instead of two. It integrates communications and call logs."

Finneran said FMC also gives enterprises ownership over their employees' phone numbers.

"That's a very subtle one that technology people overlook but business people lock onto immediately," he said. "We now own the phone number. We have unbelievable business exposure if we have customers and prospects calling … our salespeople on their personal cell numbers. If they leave the company, all their customers and prospects follow along. With FMC, now we're the only ones who know what their cell phone numbers are."

Finneran said both cellular-only and dual-mode approaches have their pros and cons when it comes to realizing these FMC benefits. Today, the cellular-only approach appears to have the most traction with enterprises because it's the easier solution. It involves a simple reprogramming of the PBX, and users are off and running. Dual-mode requires new software, some WLAN network optimization, and perhaps new devices.

Both approaches cover the basics, Finneran said. They allow employees to have one phone number across devices, one voicemail, and continuous access.

However, the cellular approach allows enterprises to use any mobile device, even a standard cell phone, with FMC. The IT department simply has to program the corporate PBX to ring both the employee's desk phone and cell phone simultaneously.

Finneran said many unified communications (UC) vendors are also developing mobile clients that run on cellular-only phones, delivering additional functionality on handsets.

"On the con side, enterprises [that use the cellular only approach] are almost certainly going to pay more money for cellular charges," he said. "Also, there is the problem of indoor cellular coverage."

Cellular signals are becoming increasingly dicey indoors, especially in offices whose windows are covered with energy-saving insulating coatings. Those coatings may save companies energy, but they also block radio signals, Finneran said. Many companies install distributed antenna systems to solve this problem, and carriers are increasingly installing this technology free of charge in order to hang onto customers.

The dual-mode approach provided by companies such as Agito and DiVitas will save companies on cellular charges, since no calls that are made on a corporate wireless LAN network will be billed to a cellular call plan.

The dual-mode approach also ensures enforcement.

"The problem with simultaneous ring is that you've got lazy users. A guy sitting at his desk, if both his phones ring, he picks up the cell phone," Finneran said. "With dual-mode, if he's in a WLAN coverage area, the call is automatically routed over the WLAN."

One major issue with the dual-mode approach is the wireless LAN network itself, he said. It has to be capable of supporting voice, which is no insignificant undertaking.

"You have to have coverage, enough access points, quality of service features, and monitoring for growth and expansion," Finneran said. "The vast majority of WLANs we have today aren't capable of supporting any significant volume of voice calling, so there is an infrastructure investment in those cases."

Another issue that comes up with the dual-mode approach is device selection. Not all phones have dual-mode antennae, and currently the vendors in this space support only two major mobile platforms: Symbian S60 and Windows Mobile 6. None of the dual-mode FMC vendors can integrate with BlackBerrys, one of the most popular smartphones in the enterprise market.

"BlackBerry is far and away the most popular smartphone in business today. Nobody's got a BlackBerry [solution] and that's a tough one," Finneran said. "You have to get control with the dialer, and you have to get into the guts of BlackBerry software to develop the type of capability [Agito and DiVitas] have. And while BlackBerry does have a developer community, they don't give full access to all the features within the BlackBerry that they need to."

Pejman Roshan, vice president of marketing for Agito, said his company is working closely with BlackBerry maker Research in Motion (RIM) to bring dual-mode FMC to RIM's platform. "It's a closed system, so we're on their timetable, not ours."

Roshan said he can't discuss the details of the work Agito is doing with RIM, but "it wouldn't be a stretch of the imagination to think we are working on a dual-mode hand-off solution [with RIM]. But the details of the whys and the whens are something we are precluded from discussing."

The future of FMC is about more than whether the dual-mode vendors can deliver functionality to BlackBerrys. Roshan said that FMC is about more than voice now and that his company isn't a "one-trick pony."

"Our vision is that mobile voice is just one application, and it's something that is a pain point now," Roshan said. "We've built a solution that has a solid foundation so that it doesn't matter what network a device is connected to. We can extract that out, so it's simple to layer other functions on top of that. Today it's voice. Tomorrow it's instant messaging and presence. Next year it's video. The future isn't about voice exclusively."

Let us know what you think about the story; email: Shamus McGillicuddy, News Editor

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